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Flashcards in Outline of the Disease Process Deck (21):
1

What are the characteristics of cancer cells?

-loss of contact inhibition
-increase in growth factor secretion
-increase in oncogene expression
-loss of tumour suppressor genes

2

What are the characteristics of a normal cell?

-oncogene expression is rare
-intermittent or co-ordinated growth factor secretion
-presence of tumour suppressor genes

3

What are the 3 stage of cancer?

-initiation
-promotion
-progression

4

What causes initiation?

-chemical
-physical
-viral

5

What causes promotion of cancer?

-growth factors
-oncogenes

6

What causes progression of cancer?

-metastasis

7

What are some examples of chemical carcinogens?

-soot and tar
-aniline dyes
-aflatoxin
-nitrogen mustard
-alcohol and smoking

8

What are some examples of physical carcinogens?

Ionising radiations:
-dose-response relationship
-radon source is mainly buildings
-increased risk by smoking
-ventilation reduced risk
Mechanism
-chromosome translocation
-gene amplification
-oncogene activation

9

What are some examples of viral carcinogens?

-herpes
-HPV
-retroviruses
-hep B

10

What are growth factors?

-polypeptide molecules
-regulate cell growth and function
-bind to cell membrane receptors
-stimulate activation of intracellular signal transduction pathways

11

Stimulation may be...

Autocrine
-cell carries receptor and secretes growth factor
-cell escapes normal control mechanism
Paracrine
-GFs acting on a cell are produced locally by the cell or its immediate neighbours

12

What is p53?

-tumour suppressor gene
-most commonly altered gene in human tumours
-normal function is as transcriptional regulator which promotes DNA repair, apoptosis and differentiation
-G1/S checkpoint control gene

13

What induced p53?

-DNA damage
-hypoxia

14

Describe metastasis.

-not random
-cascade of limited sequential steps
-involves tumour-host interactions
-survival of the fittest pertains

15

How does a tumour metastasise?

-Invades through basement membrane
-moves into extracellular matrix/connective tissue/surrounding cells
-invades blood vessels
tumour cells arrested in distant organ

16

What enzymes are involved in cell adhesion?

-cahedrins
-integrins
-CD44

17

What enzymes are involved in ECM?

-matrix metalloprotinases
-plasmin]
-cathespin

18

What is angiogenesis?

the formation of new blood vesssels

19

Give an example of a growth factor.

VEGF vascular endothelial growth factor

20

What does the anti-VEGF antibody avastin do?

-prevents interaction with receptors and activation of downstream signally pathways
-normalises vasculature

21

Why does our immune system not recognise foreign cancer cells?

-cancer cells can hide from T cells
-PD1 present on T lymphocytes
-ligand PD1 on tumour cells
-interaction of these suppresses T cell action